| 摘要 |
PURPOSE:To detect surely the arrival of a magnetic head to each track position with a simple constitution by providing a counter responding to the arrival of the magnetic head to a track zero position by a track zero position detector. CONSTITUTION:The track zero position detector 11 detects a light shielding plate 10, a track zero signal TZS is outputted from an NAND gate 24, a monostable multivibrator 32 is operated and track counters 33, 34 are reset. Thus, the magnetic head 4 at the track zero position is detected and the reset state of a monostable multivibrator circuit 381 is released. When a step signal STP is inputted at DIR=0 where a direction signal DIR designates the inward direction, the track position is counted up by the track counters 33, 34 every time the magnetic head 4 moves the track of floppy disk 3 inward. Further, when the direction signal DIR is changed to the state of DIR=1 designating the outward direction, the track position is counted down by the track counters 33, 34 every time the track is moved outward. |
